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    Angiotensin-II Receptor Blockers/ARBs

    BOXED WARNING

    Pregnancy

    When pregnancy is detected, every effort should be made to discontinue olmesartan therapy. Women of child-bearing age should be made aware of the potential risk, and olmesartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, medications that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) have been associated with reduced fetal renal function and increased fetal and neonatal morbidity and death. Use of drugs that affect the renin-angiotensin system during pregnancy can cause fetal death or injury such as hypotension, neonatal skull hypoplasia, reversible or irreversible renal failure and death. Anhydramnios and oligohydramnios have also been reported. Development of oligohydramnios may be associated with decreased fetal renal function leading to anuria and renal failure and results in fetal limb contractures, craniofacial deformation, hypotension, hypoplastic lung development, and death. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. An observational cohort study evaluating the outcomes of angiotensin receptor blockers (ARBs) use during the first trimester of pregnancy found an increased rate of major birth defects compared to non-hypertensive pregnancies, 5.4% and 3%, respectively; the difference did not reach statistical significance. The authors noted that there was a higher risk of major birth defects with ARB therapy beyond 6 weeks of gestation compared to discontinuation of ARBs before week 6, 7.3% and 2.8%, respectively. The rates of prematurity and reduced birth weight were also increased in the ARB group. There were no statistically significant differences in the rates of major birth defects, spontaneous abortions, or preterm births between women with chronic hypertension treated with an ARB versus methyldopa. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue olmesartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to olmesartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    DEA CLASS

    Rx

    DESCRIPTION

    Angiotensin II antagonist; used once daily for HTN; does not inhibit ACE and accumulate bradykinin; less likely to cause cough or angioedema than ACE inhibitors; not metabolized by the liver; lacks interactions with cytochrome P-450 inhibitors or inducers.

    COMMON BRAND NAMES

    Benicar

    HOW SUPPLIED

    Benicar/Olmesartan Medoxomil Oral Tab: 5mg, 20mg, 40mg

    DOSAGE & INDICATIONS

    For the treatment of hypertension.
    Oral dosage
    Adults

    20 mg PO once daily is the recommended starting dose for monotherapy in patients who are not volume-depleted. Increase the dose to 40 mg PO once daily if further blood pressure reduction is needed after 2 weeks of therapy. For patients who may be volume depleted, initiate therapy under close medical supervision and consider a lower starting dose. Doses greater than 40 mg/day do not appear to have a greater effect, and twice-daily dosing offers no advantage over the same total dose given once daily. If blood pressure is not controlled with olmesartan alone, a diuretic (e.g., hydrochlorothiazide) may be added.

    Adolescents 17 years

    20 mg PO once daily is the recommended starting dose for monotherapy in patients who are not volume-depleted. Increase the dose to 40 mg PO once daily if further blood pressure reduction is needed after 2 weeks of therapy. For patients who may be volume depleted, initiate therapy under close medical supervision and consider a lower starting dose. Doses greater than 40 mg/day do not appear to have a greater effect, and twice-daily dosing offers no advantage over the same total dose given once daily. If blood pressure is not controlled with olmesartan alone, a diuretic (e.g., hydrochlorothiazide) may be added.

    Children and Adolescents 6 to 16 years weighing 35 kg or more

    20 mg PO once daily initially. Increase the dose to 40 mg PO once daily if further blood pressure reduction is needed after 2 weeks of therapy. Max: 40 mg/day.

    Children and Adolescents 6 to 16 years weighing 20 to 34 kg

    10 mg PO once daily initially. Increase the dose to 20 mg PO once daily if further blood pressure reduction is needed after 2 weeks of therapy. Max: 20 mg/day.

    MAXIMUM DOSAGE

    Adults

    40 mg/day PO.

    Geriatric

    40 mg/day PO.

    Adolescents

    17 years: 40 mg/day PO.
    13 to 16 years weighing 35 kg or more: 40 mg/day PO.
    13 to 16 years weighing 20 to 34 kg: 20 mg/day PO.

    Children

    6 to 12 years weighing 35 kg or more: 40 mg/day PO.
    6 to 12 years weighing 20 to 34 kg: 20 mg/day PO.
    6 to 12 years weighing less than 20 kg: Safety and efficacy have not been established.
    1 to 5 years: Safety and efficacy have not been established.

    Infants

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    No initial dosage adjustment is recommended. Although the manufacturer recommends no initial dosage adjustment for hepatic disease, patients with moderate hepatic impairment have a 60% higher olmesartan AUC compared to normal controls. Severe hepatic impairment has not been studied. Adjust dosage cautiously based on therapeutic response.

    Renal Impairment

    No dosage adjustment is needed.

    ADMINISTRATION

    Oral Administration

    May administer without regard to food.

    Oral Liquid Formulations

    Extemporaneous Preparation of 2 mg/ml Oral Suspension:
    Add 20 olmesartan 20 mg tablets to an amber polyethylene terephthalate (PET) bottle.
    Add 50 ml of purified water to the PET bottle containing the olmesartan tablets and allow to stand for a minimum of 5 minutes.
    Shake the container for at least 1 minute and allow the suspension to stand for at least 1 minute.
    Repeat 1-minute shaking and 1-minute standing four additional times.
    Add 100 ml of Ora-Sweet and 50 ml of Ora-Plus to the suspension and shake well for at least 1 minute.
    This preparation makes 200 ml of a 2 mg/ml suspension.
    Shake the suspension well before each use.
    Store the suspension under refrigeration at 2 to 8 degrees C (36 to 45 degrees F); the extemporaneously prepared suspension may be stored for up to 4 weeks.

    STORAGE

    Benicar:
    - Store at controlled room temperature (between 68 and 77 degrees F)

    CONTRAINDICATIONS / PRECAUTIONS

    Hypotension, hypovolemia

    Olmesartan should be used with caution in patients with hypovolemia, including patients receiving high doses of diuretics. Intravascular volume and/or salt-depletion increases the risk for symptomatic hypotension, especially after administration of the first dose. Volume depletion should be corrected prior to the administration of olmesartan. In patients with possible intravascular volume depletion, initiate treatment under close medical supervision and consider using a lower start dose. Olmesartan should be used with great care in patients who exhibit signs of hypotension. If hypotension does occur, it should be corrected with an intravenous infusion of normal saline. A transient hypotensive response is not a contraindication for further treatment, which can usually be continued without difficulty once the blood pressure has stabilized.

    Heart failure, renal artery stenosis

    Olmesartan should be used with caution in patients whose renal function is critically dependent on the activity of the renin-angiotensin-aldosterone system (RAS) (e.g., patients with heart failure). Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor antagonists affect the RAS system and have caused increases in serum creatinine in susceptible individuals. Although serum creatinine returns to baseline or stabilizes in most patients with continued use, oliguria, progressive azotemia, and rarely acute renal failure have occurred in this patient population. In addition, ACEIs have been associated with azotemia in patients with unilateral or bilateral renal artery stenosis. Although olmesartan has not been studied in renal artery stenosis, similar effects to the ACEIs might be anticipated due to olmesartan's pharmacology.

    Hyperkalemia

    Olmesartan should be used with caution patients with hyperkalemia. Angiotensin II blockade can elevate serum potassium concentrations by blocking aldosterone secretion and could worsen pre-existing hyperkalemia. Hyperkalemia has been reported during post-marketing experience with olmesartan. Monitor serum electrolytes periodically during olmesartan therapy. Risk factors for the development of hyperkalemia include diabetes, renal insufficiency, and concomitant administration of potassium-sparing diuretics, potassium supplements and/or potassium-containing salt substitutes. Patients should be instructed not to use potassium supplements or salt substitutes containing potassium without consulting the prescribing physician.

    Hepatic disease

    Although the manufacturer provides no warnings or initial dosage adjustment for hepatic disease, patients with moderate hepatic impairment have a 60% higher olmesartan AUC compared to normal controls. Patients with severe hepatic impairment have not been studied. Olmesartan does not undergo metabolism by the liver, but is partially eliminated by biliary excretion (see Pharmacokinetics). Although no initial dosage adjustment of olmesartan is required, dosage increases should be made cautiously in these patients. Adjust dosage based on therapeutic response.

    ACE-inhibitor induced angioedema, angioedema

    Anaphylactic reactions (anaphylactoid reactions) and angioedema have been reported with angiotensin II receptor antagonists. Theoretically, angiotensin II receptor antagonists should be less likely than angiotensin converting enzyme inhibitors (ACEIs) to precipitate angioedema because angiotensin II receptor antagonists do not cause accumulation of kinins. However, angioedema (swelling of lips and eyelids, facial rash) has been rarely reported in patients receiving angiotensin II receptor antagonists, including in patients with a prior history of ACE-inhibitor induced angioedema. While angiotensin II receptor antagonists have been suggested as potential alternatives to ACE inhibitors for patients who experience angioedema due to a lower frequency of associated angioedema , the safety of angiotensin II receptor antagonists in patients with a prior history of ACE-inhibitor induced angioedema has not been definitively established. It is prudent to use substantial caution when prescribing angiotensin II receptor antagonists in patients with ACE-inhibitor induced angioedema. Some authors have recommended that angiotensin II receptor antagonists should be avoided in patients with a history of angioedema, especially those with ACE-inhibitor induced angioedema.

    Black patients

    Although angiotensin II receptor antagonists are effective in reducing blood pressure in Black patients (a low renin population), there is generally a smaller antihypertensive response compared to other ethnic populations. A greater proportion of Black patients will attain blood pressure goals when angiotensin II receptor antagonists are combined with a diuretic.

    Pregnancy

    When pregnancy is detected, every effort should be made to discontinue olmesartan therapy. Women of child-bearing age should be made aware of the potential risk, and olmesartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, medications that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) have been associated with reduced fetal renal function and increased fetal and neonatal morbidity and death. Use of drugs that affect the renin-angiotensin system during pregnancy can cause fetal death or injury such as hypotension, neonatal skull hypoplasia, reversible or irreversible renal failure and death. Anhydramnios and oligohydramnios have also been reported. Development of oligohydramnios may be associated with decreased fetal renal function leading to anuria and renal failure and results in fetal limb contractures, craniofacial deformation, hypotension, hypoplastic lung development, and death. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. An observational cohort study evaluating the outcomes of angiotensin receptor blockers (ARBs) use during the first trimester of pregnancy found an increased rate of major birth defects compared to non-hypertensive pregnancies, 5.4% and 3%, respectively; the difference did not reach statistical significance. The authors noted that there was a higher risk of major birth defects with ARB therapy beyond 6 weeks of gestation compared to discontinuation of ARBs before week 6, 7.3% and 2.8%, respectively. The rates of prematurity and reduced birth weight were also increased in the ARB group. There were no statistically significant differences in the rates of major birth defects, spontaneous abortions, or preterm births between women with chronic hypertension treated with an ARB versus methyldopa. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue olmesartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to olmesartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    Breast-feeding

    Breast-feeding is not recommended during olmesartan treatment. According to the manufacturer, it is not known whether olmesartan is excreted into human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made to discontinue breast-feeding or discontinue olmesartan therapy. The ACE inhibitors captopril, enalapril, benazepril, and quinapril are excreted in human breast milk in very small quantities; therefore, may be a possible alternative antihypertensives since a clinically significant risk to a breast-feeding infant is not expected unless high doses are required. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

    Infants, neonates

    Use of olmesartan is not recommended in neonates or infants younger than 1 year of age. Because the renin-angiotensin aldosterone system (RAAS) plays a critical role in kidney development, administration of drugs that act directly on the RAAS may alter normal renal development. Antihypertensive effects of olmesartan were evaluated in a randomized, double-blind trial in pediatric patients aged 1 to 16 years. Although the drug was generally well tolerated and the adverse event profile was similar to that of adults in all ages, olmesartan did not demonstrate a clinically significant antihypertensive effect in children younger than 6 years.

    Surgery

    In patients undergoing major surgery or during anesthesia with agents that lower blood pressure, olmesartan may enhance hypotensive effects via angiotensin II blockade. Therefore, olmesartan should be used with caution prior to surgery. If hypotension occurs during surgery and/or anesthesia and is considered to be due to blockade of angiotensin II formation, it can be corrected by volume expansion.

    Diabetes mellitus

     Data from the ROADMAP trial and an epidemiologic study have suggested that high-dose olmesartan may increase cardiovascular (CV) risk in diabetic patients. However, the FDA conducted a safety review of olmesartan and found no clear evidence of increased cardiovascular risk in diabetic patients. According to the FDA, the benefits of olmesartan continue to outweigh the risks in patients with hypertension. In ROADMAP, patients with type 2 diabetes mellitus received either olmesartan 40 mg/day PO or placebo to determine whether treatment with olmesartan would slow the progression of kidney disease. Unexpectedly, there was a higher number of deaths from cardiovascular cause (myocardial infarction, sudden death, or stroke) in the olmesartan group compared to placebo. Additionally, in the epidemiologic study, there was an increased risk of death in the sub-group of diabetic patients receiving high dose olmesartan (40 mg/day PO) for > 6 months compared to similar patients taking other angiotensin receptor blockers. However, high-dose olmesartan use in non-diabetic patients appeared to be associated with a decreased risk of death compared to similar patients taking other angiotensin receptor blockers. There was no difference between the groups receiving lower doses of olmesartan compared to other angiotensin blockers or those receiving therapy for < 6 months. Olmesartan is not recommended as a treatment to delay or prevent microalbuminuria in diabetic patients.

    Geriatric

    Greater sensitivity to the hypotensive effects of olmesartan is possible in geriatric patients due to an age-related decline in renal function. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents of long-term care facilities (LTCFs). According to OBRA, antihypertensive regimens should be individualized to achieve the desired outcome while minimizing adverse effects. Antihypertensives may cause dizziness, postural hypotension, fatigue, and there is an increased risk for falls. Angiotensin receptor blockers (ARBs) may cause angioedema, chronic persistent non-productive cough, and may worsen renal failure. Some agents require a gradual taper to avoid adverse consequences caused by abrupt discontinuation. There are many drug interactions that can potentiate the effects of antihypertensives. Combination therapy of an ARB with a potassium-sparing diuretic or potassium supplementation has the potential for life-threatening elevations of serum potassium.

    ADVERSE REACTIONS

    Severe

    anaphylactoid reactions / Rapid / Incidence not known
    angioedema / Rapid / Incidence not known
    hyperkalemia / Delayed / Incidence not known
    oliguria / Early / Incidence not known
    renal failure (unspecified) / Delayed / Incidence not known
    azotemia / Delayed / Incidence not known
    rhabdomyolysis / Delayed / Incidence not known
    teratogenesis / Delayed / Incidence not known

    Moderate

    elevated hepatic enzymes / Delayed / 0.1-0.1
    hypertriglyceridemia / Delayed / 1.0
    hyperglycemia / Delayed / 1.0
    hematuria / Delayed / 1.0
    sinus tachycardia / Rapid / 0.5
    peripheral edema / Delayed / 0.5
    hyperlipidemia / Delayed / 0.5
    chest pain (unspecified) / Early / 0.5
    hypercholesterolemia / Delayed / 0.5
    hyperuricemia / Delayed / 0.5
    hypotension / Rapid / Incidence not known
    orthostatic hypotension / Delayed / Incidence not known

    Mild

    dizziness / Early / 3.0-3.0
    cough / Delayed / 0.9-0.9
    sinusitis / Delayed / 1.0
    headache / Early / 1.0
    pharyngitis / Delayed / 1.0
    back pain / Delayed / 1.0
    rhinitis / Early / 1.0
    rash / Early / 0.5
    nausea / Early / 0.5
    abdominal pain / Early / 0.5
    diarrhea / Early / 1.0
    dyspepsia / Early / 0.5
    vertigo / Early / 0.5
    arthralgia / Delayed / 0.5
    myalgia / Early / 0.5
    syncope / Early / Incidence not known
    urticaria / Rapid / Incidence not known
    pruritus / Rapid / Incidence not known
    asthenia / Delayed / Incidence not known
    alopecia / Delayed / Incidence not known
    vomiting / Early / Incidence not known
    weight loss / Delayed / Incidence not known

    DRUG INTERACTIONS

    Acarbose: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acetaminophen; Dichloralphenazone; Isometheptene: (Moderate) Isometheptene has sympathomimetic properties. Patients taking antihypertensive agents may need to have their therapy modified. Careful blood pressure monitoring is recommended.
    Acetaminophen; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Acetaminophen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Acrivastine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Aldesleukin, IL-2: (Moderate) Angiotensin II receptor antagonists may potentiate the hypotension seen with aldesleukin, IL 2.
    Alemtuzumab: (Moderate) Alemtuzumab may cause hypotension. Careful monitoring of blood pressure and hypotensive symptoms is recommended especially in patients with ischemic heart disease and in patients on antihypertensive agents.
    Aliskiren: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin II receptor antagonists (ARBs) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, hypotension, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ARBs and aliskiren, do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Amlodipine: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin II receptor antagonists (ARBs) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, hypotension, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ARBs and aliskiren, do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin II receptor antagonists (ARBs) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, hypotension, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ARBs and aliskiren, do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin II receptor antagonists (ARBs) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, hypotension, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ARBs and aliskiren, do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Aliskiren; Valsartan: (Major) Aliskiren-containing products are contraindicated in combination with angiotensin II receptor antagonists (ARBs) in patients with diabetes mellitus. In general, avoid combined use of two renin-angiotensin-aldosterone system (RAAS) inhibitors, particularly in patients with CrCl less than 60 mL/minute. Combination therapy increases the risk for hyperkalemia, renal impairment, hypotension, and other side effects. Most patients receiving a comination of two RAAS inhibitors, such as ARBs and aliskiren, do not obtain any additional benefit compared to monotherapy. Closely monitor blood pressure, renal function, and electrolytes if aliskiren must be combined with another RAAS inhibitor. In the ALTITUDE trial, patients with type 2 diabetes and renal impairment, a population at high risk for cardiovascular and renal events, were given aliskiren in addition to ACE inhibitors or ARBs. The trial was stopped early because aliskiren was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension. In the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) trial, no additional benefit over monotherapy was seen in patients receiving the combination of losartan and lisinopril compared to monotherapy; however, there was an increased incidence of hyperkalemia and acute renal injury.
    Alogliptin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Alpha-glucosidase Inhibitors: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Alprostadil: (Minor) The concomitant use of systemic alprostadil injection and antihypertensive agents, such as angiotensin II receptor antagonists (angiotensin receptor blockers, or ARBs), may cause additive hypotension. Caution is advised with this combination. Systemic drug interactions with the urethral suppository (MUSE) or alprostadil intracavernous injection are unlikely in most patients because low or undetectable amounts of the drug are found in the peripheral venous circulation following administration. In those men with significant corpora cavernosa venous leakage, hypotension might be more likely. Use caution with in-clinic dosing for erectile dysfunction (ED) and monitor for the effects on blood pressure. However, in clinical trials with alprostadil intracavernous injection, anti-hypertensive agents had no apparent effect on the safety and efficacy of alprostadil.
    Amifostine: (Major) Patients receiving angiotensin II receptor antagonists should be closely monitored during amifostine infusions due to additive effects. Patients receiving amifostine at doses recommended for chemotherapy should have antihypertensive therapy interrupted 24 hours preceding administration of amifostine. If the antihypertensive cannot be stopped, patients should not receive amifostine.
    Amiloride: (Major) Potassium-sparing diuretics, such as amiloride, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Amiloride; Hydrochlorothiazide, HCTZ: (Major) Potassium-sparing diuretics, such as amiloride, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Amobarbital: (Moderate) Concurrent use of amobarbital with antihypertensive agents may lead to hypotension. Monitor for decreases in blood pressure during times of coadministration.
    Amphetamine; Dextroamphetamine Salts: (Minor) Amphetamines increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure is advised.
    Amyl Nitrite: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Angiotensin II: (Moderate) Angiotensin II receptor antagonists (angiotensin receptor blockers, or ARBs) may decrease the response to angiotensin II. Angiotensin II is a naturally occurring peptide hormone of the renin-angiotensin-aldosterone system (RAAS) that causes vasoconstriction and an increase in blood pressure. ARBs block the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively blocking the binding of angiotensin II to the angiotensin receptor in many tissues.
    Angiotensin-converting enzyme inhibitors: (Major) Most patients receiving the combination of two renin-angiotensin-aldosterone system (RAAS) inhibitors, such as angiotensin-converting enzyme inhibitors (ACE inhibitors) and angiotensin II receptor antagonists (ARBs) do not obtain any additional benefit compared to monotherapy. Combination therapy has been associated with an increased risk of diarrhea, hypotension, syncope, hyperkalemia, and renal dysfunction resulting in dialysis, doubling of serum creatinine, and death in clinical studies. The risk of hyperkalemia is particularly high in patients with renal impairment (stage 3a or higher kidney disease). In general, avoid combined use of these drugs together. Patients who must receive concomitant therapy with ACE inhibitors and ARBs should be closely monitored for renal dysfunction, hypotension, and hyperkalemia. Closely monitor blood pressure, renal function, and electrolytes.
    Apomorphine: (Moderate) Use of angiotensin II receptor antagonists and apomorphine together can increase the hypotensive effects of apomorphine. Monitor blood pressure regularly during use of this combination.
    Apraclonidine: (Minor) Alpha blockers as a class may reduce heart rate and blood pressure. While no specific drug interactions have been identified with systemic agents and apraclonidine during clinical trials, it is theoretically possible that additive blood pressure reductions could occur when apraclonidine is combined with the use of antihypertensive agents. Patients using cardiovascular drugs concomitantly with apraclonidine should have their pulse and blood pressure monitored periodically.
    Aripiprazole: (Minor) Aripiprazole may enhance the hypotensive effects of antihypertensive agents.
    Articaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin II receptor antagonists, antagonize the vasopressor effects of parenteral epinephrine.
    Asenapine: (Moderate) Secondary to alpha-blockade, asenapine can produce vasodilation that may result in additive effects during concurrent use of antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of asenapine and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Baclofen: (Moderate) Baclofen has been associated with hypotension. Concurrent use with baclofen and antihypertensive agents may result in additive hypotension. Dosage adjustments of the antihypertensive medication may be required.
    Benzphetamine: (Minor) Benzphetamine may increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure is advised.
    Bosentan: (Moderate) Although no specific interactions have been documented, bosentan has vasodilatory effects and may contribute additive hypotensive effects when given with angiotensin II receptor antagonists. Losartan has no effect on plasma concentrations of bosentan. However, bosentan may theoretically induce the metabolism of losartan via CYP2C9 isoenzymes (clinical significance unknown).
    Brexpiprazole: (Moderate) Due to brexpiprazole's antagonism at alpha 1-adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents.
    Brompheniramine; Carbetapentane; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Brompheniramine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Brompheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Brompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Bupivacaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin II receptor antagonists, antagonize the vasopressor effects of parenteral epinephrine.
    Cabergoline: (Moderate) Cabergoline should be used cautiously with antihypertensive agents, including angiotensin II receptor antagonists. Cabergoline has been associated with hypotension. Initial doses of cabergoline higher than 1 mg may produce orthostatic hypotension. It may be advisable to monitor blood pressure.
    Calcium Phosphate, Supersaturated: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin II receptor antagonists, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Canagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Carbetapentane; Chlorpheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Phenylephrine; Pyrilamine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbetapentane; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbidopa; Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Carbidopa; Levodopa; Entacapone: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Carbinoxamine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbinoxamine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbinoxamine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Carbinoxamine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Carbinoxamine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Cariprazine: (Moderate) Orthostatic vital signs should be monitored in patients who are at risk for hypotension, such as those receiving cariprazine in combination with antihypertensive agents. Atypical antipsychotics may cause orthostatic hypotension and syncope, most commonly during treatment initiation and dosage increases. Patients should be informed about measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning, or rising slowly from a seated position. Consider a cariprazine dose reduction if hypotension occurs.
    Cetirizine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlophedianol; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chloroprocaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
    Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Dihydrocodeine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Chlorpheniramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Chlorpheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Clozapine: (Moderate) Clozapine used concomitantly with the antihypertensive agents can increase the risk and severity of hypotension by potentiating the effect of the antihypertensive drug.
    Cocaine: (Major) Use of cocaine with antihypertensive agents may increase the antihypertensive effects of the antihypertensive medications or may potentiate cocaine-induced sympathetic stimulation.
    Codeine; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Codeine; Phenylephrine; Promethazine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Co-Enzyme Q10, Ubiquinone: (Moderate) Co-enzyme Q10, ubiquinone (CoQ10) may lower blood pressure. CoQ10 use in combination with antihypertensive agents may lead to additional reductions in blood pressure in some individuals. Patients who choose to take CoQ10 concurrently with antihypertensive medications should receive periodic blood pressure monitoring. Patients should be advised to inform their prescriber of their use of CoQ10.
    Colesevelam: (Moderate) Colesevelam decreases the Cmax and AUC of olmesartan by approximately 28% and 39%, respectively. Administer olmesartan at least 4 hours before colesevelam.
    Cyclosporine: (Moderate) Coadministration of cyclosporine and an angiotensin II receptor antagonist, like olmesartan, may increase the risk of hyperkalemia and reduced renal function. In response to cyclosporine-induced renal afferent vasoconstriction and glomerular hypoperfusion, angiotensin II is required to maintain an adequate glomerular filtration rate. Inhibition of angiotensin-converting enzyme (ACE) could reduce renal function acutely. Several cases of acute renal failure have been associated with the addition of enalapril to cyclosporine therapy in renal transplant patients. Also, cyclosporine can cause hyperkalemia, and inhibition of angiotensin II leads to reduced aldosterone concentrations, which can increase the serum potassium concentration. Closely monitor renal function and serum potassium concentrations in patients receiving cyclosporine concurrently with olmesartan.
    Dapagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Desloratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dexbrompheniramine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Dextromethorphan; Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
    Diazoxide: (Moderate) Additive hypotensive effects can occur with the concomitant administration of diazoxide with other antihypertensive agents. This interaction can be therapeutically advantageous, but dosages must be adjusted accordingly. The manufacturer advises that IV diazoxide should not be administered to patients within 6 hours of receiving beta-blockers, hydralazine, methyldopa, minoxidil, nitrites, prazosin, reserpine, or other antihypertensive agents.
    Diethylpropion: (Moderate) Diethylpropion has vasopressor effects and may limit the benefit of angiotensin II receptor antagonists. Although leading drug interaction texts differ in the potential for an interaction between diethylpropion and this group of antihypertensive agents, these effects are likely to be clinically significant and have been described in hypertensive patients on these medications.
    Digoxin: (Moderate) Caution should be exercised when administering digoxin with drugs that may cause a significant deterioration in renal function including angiotensin II receptor antagonists. A decline in glomerular filtration or tubular secretion may impair the excretion of digoxin. Close monitoring of serum digoxin concentrations is essential to avoid enhanced toxicity.
    Dihydrocodeine; Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Diphenhydramine; Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Diphenhydramine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Drospirenone: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Estetrol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Ethinyl Estradiol: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function.
    Duloxetine: (Moderate) Orthostatic hypotension and syncope have been reported during duloxetine administration. The concurrent administration of antihypertensive agents and duloxetine may increase the risk of hypotension. Monitor blood pressure if the combination is necessary.
    Eltrombopag: (Moderate) Use caution and monitor blood pressure closely if eltrombopag and olmesartan are coadministered. Eltrombopag is an inhibitor of the transporter OATP1B1. Drugs that are substrates for this transporter, such as olmesartan, may exhibit an increase in systemic exposure if coadministered with eltrombopag.
    Empagliflozin; Linagliptin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Empagliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Enflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Ephedrine: (Moderate) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
    Ephedrine; Guaifenesin: (Moderate) The cardiovascular effects of sympathomimetics, such as ephedrine, may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Blood pressure and heart rates should be monitored closely to confirm that the desired antihypertensive effect is achieved.
    Epinephrine: (Moderate) Antihypertensives, including angiotensin II receptor antagonists, antagonize the vasopressor effects of parenteral epinephrine.
    Eplerenone: (Major) Monitor serum potassium and serum creatinine concentrations within 3 to 7 days of initiating coadministration of eplerenone and angiotensin II receptor antagonists (ARBs). Hyperkalemia risk is increased when eplerenone is used with ARBs. Patients who develop hyperkalemia may continue eplerenone with proper dose adjustment; eplerenone dose reduction decreases potassium concentrations.
    Epoprostenol: (Moderate) Angiotensin II receptor antagonists can enhance the hypotensive effects of antihypertensive agents if given concomitantly. This additive effect may be desirable, but dosages must be adjusted accordingly.
    Ertugliflozin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Estradiol Cypionate; Medroxyprogesterone: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormonal contraceptives should be monitored for antihypertensive effectiveness.
    Estradiol: (Minor) Estrogens can induce fluid retention and may increase blood pressure in some patients; patients who are receiving antihypertensive agents concurrently with hormonal contraceptives should be monitored for antihypertensive effectiveness.
    Etomidate: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Fexofenadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Finerenone: (Moderate) Monitor serum potassium concentrations closely if finerenone and angiotensin II receptor antagonists are used together. Concomitant use may increase the risk of hyperkalemia.
    Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
    Fospropofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Gemfibrozil: (Moderate) Coadministration may result in an increase in olmesartan exposure. A dose reduction of olmesartan may be required if used concomitantly with gemfibrozil. Use olmesartan and gemfibrozil together with caution. Olmesartan is a substrate of the OATP1B1 transporter. Gemfibrozil inhibits OATP1B1.
    General anesthetics: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Glipizide; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Glyburide; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Guaifenesin; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Guaifenesin; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Haloperidol: (Moderate) In general, antipsychotics like haloperidol should be used cautiously with antihypertensive agents due to the possibility of additive hypotension.
    Halothane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Hydrocodone; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Hydrocodone; Potassium Guaiacolsulfonate; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Hydrocodone; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Ibritumomab Tiuxetan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Ibuprofen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Iloperidone: (Moderate) Secondary to alpha-blockade, iloperidone can produce vasodilation that may result in additive effects during concurrent use with antihypertensive agents. The potential reduction in blood pressure can precipitate orthostatic hypotension and associated dizziness, tachycardia, and syncope. If concurrent use of iloperidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Iloprost: (Moderate) Angiotensin II receptor antagonists can enhance the hypotensive effects of antihypertensive agents if given concomitantly. This additive effect may be desirable, but dosages must be adjusted accordingly.
    Incretin Mimetics: (Moderate) Angiotensin II receptor antagonists may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving these drugs concomitantly should be monitored for changes in glycemic control.
    Indapamide: (Moderate) The effects of indapamide may be additive when administered with other antihypertensive agents or diuretics. In some patients, this may be desirable, but orthostatic hypotension may occur. Angiotensin II receptor antagonists tend to reverse the potassium loss, but not the serum uric acid rise associated with thiazide diuretic monotherapy.
    Insulins: (Moderate) Monitor patients receiving angiotensin II receptor antagonists concomitantly with insulin for changes in glycemic control. Angiotensin II receptor antagonists may enhance the hypoglycemic effects of insulin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease.
    Intravenous Lipid Emulsions: (Moderate) High doses of fish oil supplements may produce a blood pressure lowering effect. It is possible that additive reductions in blood pressure may be seen when fish oils are used in a patient already taking antihypertensive agents.
    Isocarboxazid: (Moderate) Additive hypotensive effects may be seen when isocarboxazid is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during concurrent therapy of isocarboxazid with angiotensin II receptor antagonists. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider during concurrent use of isocarboxazid and an angiotensin II receptor antagonist.
    Isoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Isoproterenol: (Moderate) The pharmacologic effects of isoproterenol may cause an increase in blood pressure. If isoproterenol is used concomitantly with antihypertensives, the blood pressure should be monitored as the administration of isoproterenol can compromise the effectiveness of antihypertensive agents.
    Isosorbide Dinitrate, ISDN: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Isosorbide Mononitrate: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Ketamine: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Levodopa: (Moderate) Concomitant use of antihypertensive agents with levodopa can result in additive hypotensive effects.
    Linagliptin; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Lisdexamfetamine: (Minor) Lisdexamfetamine may increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure is advised.
    Lithium: (Moderate) Angiotensin II receptor antagonists (Angiotensin Receptor Blockers, or ARBs) should be used very cautiously, if at all, in patients already receiving lithium. The risk of lithium toxicity may be increased in patients receiving ARBs. ARBs decrease lithium clearance, possibly as a result of sodium depletion which leads to increased renal tubular reabsorption of lithium. Start with lower doses of lithium or reduce dosage, while frequently monitoring serum lithium concentrations and for signs/symptoms of lithium toxicity.
    Loop diuretics: (Moderate) Coadministration of furosemide and Angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensin II receptor antagonists may result in severe hypotension and deterioration in renal function, including renal failure. Hyponatremia or hypovolemia predisposes patients to acute hypotensive episodes following initiation of ACE inhibitor therapy. While ACE inhibitors and loop diuretics are routinely administered together in the treatment of heart failure, if an ACE inhibitor is to be administered to a patient receiving furosemide, initial doses should be conservative.
    Loratadine; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Lovastatin; Niacin: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Lurasidone: (Moderate) Due to the antagonism of lurasidone at alpha-1 adrenergic receptors, the drug may enhance the hypotensive effects of alpha-blockers and other antihypertensive agents. If concurrent use of lurasidone and antihypertensive agents is necessary, patients should be counseled on measures to prevent orthostatic hypotension, such as sitting on the edge of the bed for several minutes prior to standing in the morning and rising slowly from a seated position. Close monitoring of blood pressure is recommended until the full effects of the combination therapy are known.
    Magnesium Sulfate; Potassium Sulfate; Sodium Sulfate: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Meglitinides: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Mestranol; Norethindrone: (Minor) Estrogen containing oral contraceptives can induce fluid retention and may increase blood pressure in some patients; monitor patients receiving concurrent therapy to confirm that the desired antihypertensive effect is being obtained.
    Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Repaglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control. (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Rosiglitazone: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Saxagliptin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Metformin; Sitagliptin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Methamphetamine: (Minor) Methamphetamine may increase both systolic and diastolic blood pressure and may counteract the activity of some antihypertensive agents, such as angiotensin II receptor antagonists. Close monitoring of blood pressure is advised.
    Methohexital: (Moderate) Concurrent use of methohexital and antihypertensive agents increases the risk of developing hypotension.
    Methylphenidate Derivatives: (Moderate) Periodic evaluation of blood pressure is advisable during concurrent use of methylphenidate derivatives and antihypertensive agents, particularly during initial coadministration and after dosage increases of methylphenidate. Methylphenidate derivatives can reduce the hypotensive effect of antihypertensive agents such as angiotensin II receptor antagonists.
    Miglitol: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Milrinone: (Moderate) Concurrent administration of antihypertensive agents could lead to additive hypotension when administered with milrinone. Titrate milrinone dosage according to hemodynamic response.
    Naproxen; Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Nateglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Nefazodone: (Minor) Although relatively infrequent, nefazodone may cause orthostatic hypotension in some patients; this effect may be additive with antihypertensive agents. Blood pressure monitoring is recommended. Dependent upon clinical response, dosage adjustments of either drug may be necessary.
    Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with antihypertensive agents.
    Niacin, Niacinamide: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Niacin; Simvastatin: (Moderate) Cutaneous vasodilation induced by niacin may become problematic if high-dose niacin is used concomitantly with other antihypertensive agents. This effect is of particular concern in the setting of acute myocardial infarction, unstable angina, or other acute hemodynamic compromise.
    Nitrates: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Nitroglycerin: (Moderate) Concomitant use of nitrates with other antihypertensive agents can cause additive hypotensive effects. Dosage adjustments may be necessary.
    Nitroprusside: (Moderate) Additive hypotensive effects may occur when nitroprusside is used concomitantly with other antihypertensive agents. Dosages should be adjusted carefully, according to blood pressure.
    Nonsteroidal antiinflammatory drugs: (Moderate) Nonsteroidal antiinflammatory drugs (NSAIDs) (including selective COX-2 inhibitors) may alter the response to Angiotensin II receptor blockers due to inhibition of vasodilatory prostaglandins. Among NSAIDs, indomethacin, naproxen, and piroxicam may have the greatest pressor effect, while the effects of sulindac and nabumetone may be significantly less. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function who are being treated with NSAIDs, coadministration of angiotensin II receptor antagonists may result in further deterioration of renal function, including acute renal failure. These effects are usually reversible.
    Olanzapine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
    Olanzapine; Fluoxetine: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
    Olanzapine; Samidorphan: (Moderate) Olanzapine may induce orthostatic hypotension and thus enhance the effects of antihypertensive agents.
    Oxymetazoline: (Major) The vasoconstricting actions of oxymetazoline, an alpha adrenergic agonist, may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. If these drugs are used together, closely monitor for changes in blood pressure.
    Paliperidone: (Moderate) Paliperidone may cause orthostatic hypotension, thereby enhancing the hypotensive effects of antihypertensive agents. Orthostatic vital signs should be monitored in patients receiving paliperidone and angiotensin II receptor antagonists who are susceptible to hypotension.
    Pentoxifylline: (Moderate) Pentoxifylline has been used concurrently with antihypertensive drugs (beta blockers, diuretics) without observed problems. Small decreases in blood pressure have been observed in some patients treated with pentoxifylline; periodic systemic blood pressure monitoring is recommended for patients receiving concomitant antihypertensives. If indicated, dosage of the antihypertensive agents should be reduced.
    Phenelzine: (Moderate) Additive hypotensive effects may be seen when phenelzine is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during concurrent therapy of phenelzine with angiotensin II receptor antagonists. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider during concurrent use of phenelzine and angiotensin II receptor antagonists.
    Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Pioglitazone; Metformin: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of metformin by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. ARBs may rarely reduce renal function, a risk factor for reduced renal clearance of metformin. Patients receiving these drugs together should be monitored for changes in renal function and glycemic control.
    Polyethylene Glycol; Electrolytes: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Polyethylene Glycol; Electrolytes; Ascorbic Acid: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists.
    Potassium Phosphate: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Potassium Phosphate; Sodium Phosphate: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Potassium: (Moderate) Monitor serum potassium concentrations closely if potassium supplements and angiotensin II receptor antagonists are used together. Concomitant use may increase the risk of hyperkalemia.
    Pramlintide: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of pramlintide by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with pramlintide should be monitored for changes in glycemic control.
    Prazosin: (Moderate) razosin is well-known to produce a 'first-dose' phenomenon. Some patients develop significant hypotension shortly after administration of the first dose. The first dose response (acute postural hypotension) of prazosin may be exaggerated in patients who are receiving beta-adrenergic blockers, diuretics, or other antihypertensive agents. Concomitant administration of prazosin with other antihypertensive agents is not prohibited, however. This can be therapeutically advantageous, but lower dosages of each agent should be used.
    Prilocaine; Epinephrine: (Moderate) Antihypertensives, including angiotensin II receptor antagonists, antagonize the vasopressor effects of parenteral epinephrine.
    Procainamide: (Moderate) Procainamide can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents. Intravenous administration of procainamide is more likely to cause hypotensive effects.
    Procaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents.
    Promethazine; Phenylephrine: (Moderate) The cardiovascular effects of sympathomimetics may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Well-controlled hypertensive patients receiving phenylephrine at recommended doses do not appear at high risk for significant elevations in blood pressure; however, increased blood pressure (especially systolic hypertension) has been reported in some patients.
    Propofol: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    Pseudoephedrine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Pseudoephedrine; Triprolidine: (Moderate) The cardiovascular effects of pseudoephedrine may reduce the antihypertensive effects produced by angiotensin II receptor antagonists. Monitor heart rate and blood pressure.
    Quinidine: (Moderate) Quinidine can decrease blood pressure and should be used cautiously in patients receiving antihypertensive agents due to the potential for additive hypotension.
    Rasagiline: (Moderate) Additive hypotensive effects may be seen when rasagiline is combined with angiotensin II receptor antagonists. Careful monitoring of blood pressure is suggested during coadministration. Patients should be instructed to rise slowly from a sitting position, and to report syncope or changes in blood pressure or heart rate to their health care provider.
    Repaglinide: (Moderate) Angiotensin II receptor antagonists (ARB) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Risperidone: (Moderate) Risperidone may induce orthostatic hypotension and thus enhance the hypotensive effects of angiotensin II receptor antagonists. Lower initial doses or slower dose titration of risperidone may be necessary in patients receiving angiotensin II receptor antagonists concomitantly.
    Sevoflurane: (Moderate) General anesthetics can potentiate the hypotensive effects of antihypertensive agents.
    SGLT2 Inhibitors: (Moderate) Patients receiving these drugs concomitantly should be monitored for changes in blood pressure, volume status, renal function, serum potassium and other electrolytes, and for glycemic control. When an SGLT2 inhibitor is initiated, mild diuresis and naturesis occurs, producing intravascular volume contraction. These effects may be additive to certain antihypertensive medications, such as the angiotensin II receptor antagonists (also known as angiotensin receptor blockers or ARBs). Patients with impaired renal function (eGFR less than 60 mL/minute/1.73 m2), low systolic blood pressure, or who are elderly may also be at a greater risk. Volume status should be assessed and corrected. In addition, some SGLT2 inhibitors, like canagliflozin, can increase serum potassium. Monitor serum potassium levels periodically and monitor for hyperkalemia. ARBs may also enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity.
    Silodosin: (Moderate) During clinical trials with silodosin, the incidence of dizziness and orthostatic hypotension was higher in patients receiving concomitant antihypertensive treatment. Thus, caution is advisable when silodosin is administered with antihypertensive agents.
    Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin II receptor antagonists, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Moderate) Use caution when prescribing sodium picosulfate; magnesium oxide; anhydrous citric acid in patients taking concomitant medications that may affect renal function such as angiotensin II receptor antagonists. In addition, use caution in patients receiving drugs where hypokalemia is a particular risk.
    Spironolactone: (Major) Potassium-sparing diuretics, such as spironolactone, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Spironolactone; Hydrochlorothiazide, HCTZ: (Major) Potassium-sparing diuretics, such as spironolactone, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin II receptor antagonist and trimethoprim is necessary. Avoid concomitant use and consider alternative antibiotic therapy in patients with additional risk factors for hyperkalemia including patients age greater than 65 years old, those with underlying disorders of potassium metabolism, renal insufficiency, or those requiring high doses of trimethoprim. Amongst patients over the age of 65, concomitant use has been associated with a 2 to 7-fold increased risk of significant hyperkalemia compared to other antibiotics. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
    Sulfonylureas: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Tetracaine: (Moderate) Local anesthetics may cause additive hypotension in combination with antihypertensive agents. Use extreme caution with the concomitant use of tetracaine and antihypertensive agents.
    Thiazolidinediones: (Moderate) Angiotensin II receptor antagonists (ARBs) may enhance the hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. In addition, angiotensin II receptor antagonists have been associated with a reduced incidence in the development of new-onset diabetes in patients with hypertension or other cardiac disease. Patients receiving an ARB in combination with antidiabetic agents should be monitored for changes in glycemic control.
    Thiopental: (Moderate) Concurrent use of thiopental and alpha-blockers or antihypertensive agents increases the risk of developing hypotension.
    Thiothixene: (Moderate) Thiothixene should be used cautiously in patients receiving antihypertensive agents. Additive hypotensive effects are possible.
    Tizanidine: (Moderate) Concurrent use of tizanidine with antihypertensive agents can result in significant hypotension. Caution is advised when tizanidine is to be used in patients receiving concurrent antihypertensive therapy.
    Tolvaptan: (Moderate) Monitor serum potassium concentrations closely if tolvaptan and angiotensin II receptor blockers are used together. In clinical studies, hyperkalemia was reported at a rate 1% to 2% higher when tolvaptan was administered with angiotensin II receptor blockers compared to administration of these medications with placebo.
    Tranylcypromine: (Contraindicated) The use of hypotensive agents and tranylcypromine is contraindicated by the manufacturer of tranylcypromine because the effects of hypotensive agents may be markedly potentiated.
    Trazodone: (Minor) Due to additive hypotensive effects, patients receiving antihypertensive agents concurrently with trazodone may have excessive hypotension. Decreased dosage of the antihypertensive agent may be required when given with trazodone.
    Triamterene: (Major) Potassium-sparing diuretics, such as triamterene, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Triamterene; Hydrochlorothiazide, HCTZ: (Major) Potassium-sparing diuretics, such as triamterene, should be used with caution in patients taking drugs that may increase serum potassium levels such as angiotensin II receptor antagonists. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Coadministration may also result in increases in serum creatinine in heart failure patients.
    Trimethoprim: (Moderate) Monitor for hyperkalemia if concomitant use of an angiotensin II receptor antagonist and trimethoprim is necessary. Avoid concomitant use and consider alternative antibiotic therapy in patients with additional risk factors for hyperkalemia including patients age greater than 65 years old, those with underlying disorders of potassium metabolism, renal insufficiency, or those requiring high doses of trimethoprim. Amongst patients over the age of 65, concomitant use has been associated with a 2 to 7-fold increased risk of significant hyperkalemia compared to other antibiotics. Trimethoprim has a potassium-sparing effect on the distal nephron and may induce hyperkalemia, especially in those with pre-existing risk factors.
    Yohimbine: (Moderate) Yohimbine can increase blood pressure and therefore can antagonize the therapeutic action of antihypertensive agents. Use with particular caution in hypertensive patients with high or uncontrolled blood pressure.
    Ziprasidone: (Minor) Ziprasidone is a moderate antagonist of alpha-1 receptors and may cause orthostatic hypotension with or without tachycardia, dizziness, or syncope. Additive hypotensive effects are possible if ziprasidone is used concurrently with antihypertensive agents.

    PREGNANCY AND LACTATION

    Pregnancy

    When pregnancy is detected, every effort should be made to discontinue olmesartan therapy. Women of child-bearing age should be made aware of the potential risk, and olmesartan should only be given after careful counseling and consideration of individual risks and benefits. When used during the second and third trimesters, medications that affect the renin-angiotensin system (e.g., ACE inhibitors, angiotensin II receptor antagonists) have been associated with reduced fetal renal function and increased fetal and neonatal morbidity and death. Use of drugs that affect the renin-angiotensin system during pregnancy can cause fetal death or injury such as hypotension, neonatal skull hypoplasia, reversible or irreversible renal failure and death. Anhydramnios and oligohydramnios have also been reported. Development of oligohydramnios may be associated with decreased fetal renal function leading to anuria and renal failure and results in fetal limb contractures, craniofacial deformation, hypotension, hypoplastic lung development, and death. Retrospective data indicate that first trimester use of ACE inhibitors has been associated with a potential risk of birth defects. However, a much larger observational study (n = 465,754) found that the risk of birth defects was similar in infants exposed to ACE inhibitors during the first trimester, in infants exposed to other antihypertensives during the first trimester, and in those whose mothers were hypertensive but were not treated. Infants born to mothers with hypertension, either treated or untreated, had a higher risk of birth defects than those born to mothers without hypertension. The authors concluded that the presence of hypertension likely contributed to the development of birth defects rather than the use of medications. An observational cohort study evaluating the outcomes of angiotensin receptor blockers (ARBs) use during the first trimester of pregnancy found an increased rate of major birth defects compared to non-hypertensive pregnancies, 5.4% and 3%, respectively; the difference did not reach statistical significance. The authors noted that there was a higher risk of major birth defects with ARB therapy beyond 6 weeks of gestation compared to discontinuation of ARBs before week 6, 7.3% and 2.8%, respectively. The rates of prematurity and reduced birth weight were also increased in the ARB group. There were no statistically significant differences in the rates of major birth defects, spontaneous abortions, or preterm births between women with chronic hypertension treated with an ARB versus methyldopa. In rare cases when another antihypertensive agent cannot be used to treat a pregnant patient, serial ultrasound examinations should be performed to assess the intraamniotic environment. If oligohydramnios is observed, discontinue olmesartan unless it is considered life-saving for the mother. It should be noted that oligohydramnios may not appear until after the fetus has sustained irreversible injury. Closely observe newborns with histories of in utero exposure to olmesartan for hypotension, oliguria, and hyperkalemia. If oliguria or hypotension occurs, blood pressure and renal perfusion support may be required, as well as exchange transfusion or dialysis to reverse hypotension and/or support decreased renal function.

    Breast-feeding is not recommended during olmesartan treatment. According to the manufacturer, it is not known whether olmesartan is excreted into human milk. Because of the potential for adverse effects on the nursing infant, a decision should be made to discontinue breast-feeding or discontinue olmesartan therapy. The ACE inhibitors captopril, enalapril, benazepril, and quinapril are excreted in human breast milk in very small quantities; therefore, may be a possible alternative antihypertensives since a clinically significant risk to a breast-feeding infant is not expected unless high doses are required. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

    MECHANISM OF ACTION

    Mechanism of Action: Olmesartan antagonizes angiotensin II at the AT1 receptor subtype in vascular smooth muscle. Two angiotensin II receptors, AT1 and AT2, have been identified; olmesartan exhibits more than 12,500-fold greater affinity for the AT1 receptor than the AT2 receptor. The AT2 subtype is not known to mediate cardiovascular homeostasis. Angiotensin II is the primary vasoactive hormone of the renin-angiotensin system and plays an important role in the pathophysiology of hypertension and congestive heart failure. Besides being a potent vasoconstrictor, the effects of angiotensin II include stimulation of the synthesis and release of aldosterone, cardiac stimulation, and renal reabsorption of sodium. By blocking the effects of angiotensin II, olmesartan decreases systemic vascular resistance without a marked change in heart rate. Circulating levels of both renin and angiotensin II rise in response to blockade of AT1 receptors; however, the increases in renin and angiotensin II do not overcome the effect of olmesartan on blood pressure. Because olmesartan does not inhibit angiotensin-converting enzyme (ACE), it does not affect the breakdown of bradykinin. Similar to ACE inhibitors, angiotensin II antagonists reduce LVH, do not worsen insulin resistance or serum lipid profiles, and generally do not cause sexual dysfunction.

    PHARMACOKINETICS

    Olmesartan is administered orally. It is highly bound to plasma proteins (99%). Following conversion of olmesartan medoxomil to the active drug olmesartan, there is virtually no further metabolism. Olmesartan appears to be eliminated in a biphasic manner with a terminal elimination half-life of approximately 13 hours. Steady state levels are achieved in 3—5 days and no accumulation in plasma occurs with once-daily dosing. Almost half of the administered dose (35—50%) is eliminated in urine, while the remainder is eliminated in the feces via biliary excretion.
     
    Affected cytochrome P450 isoenzymes and drug transporters: none
    Olmesartan is not metabolized by the hepatic cytochrome P450 enzyme system and has no effects in vitro on CYP450 enzymes.

    Oral Route

    Olmesartan medoxomil is rapidly and completely converted (de-esterified) to olmesartan during absorption from the gastrointestinal tract. The absolute bioavailability of olmesartan is approximately 26%. Peak concentrations are reached about 1—2 hours after dosing. Food does not affect the bioavailability of the drug.